The Sit and Reach test is one way to measure flexibility: www.adultfitnesstest.org/testInstructions/
Just be very careful with this test and make sure you're warmed up before you start it.
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford
"No matter how slow you go, you are still lapping everybody on the couch."